A venous Doppler ultrasound is a diagnostic test used to check the circulation in the large veins in the legs (or sometimes the arms). This exam shows any blockage in the veins by a blood clot or “thrombus” formation.

It may help diagnose a blood clot, venous insufficiency, arterial occlusion (closing), abnormalities in arterial blood flow caused by a narrowing, or trauma to the arteries.